Method and apparatus for determining the closed loop power control set point in a wireless packet data communication system

In a first communication device in which at least two channels are transmitted and in which a first channel is transmitted during a larger percentage of the duration of a communication service than the remaining channels, a method for determining a power control set point at a receiver of said at least two channels, comprising the steps of:

• demodulating said first channel of a received signal;
• demodulating said remaining channels of said received signal;
• and
• determining said power control set point in accordance with said demodulated first channel, wherein said step of determining said power control set point comprises the steps of,
• calculating a pilot bit error rate,
• calculating said power control set point in accordance with said pilot bit error rate,
• determining said pilot variance, wherein said step of determining said pilot variance comprises the steps of,
• computing energies of said demodulated pilot symbols, and
• calculating the variance of said energies of said demodulated pilot symbols, wherein said step of calculating the variance comprises the steps of,
• filtering said pilot symbol energies,
• squaring said filtered demodulated pilot symbol energy to provide an average squared pilot symbol energy;
• squaring said pilot symbol energies, filtering said squared demodulated pilot symbols to provide a squared average pilot symbol energy,
• summing said average squared pilot symbol energy and said squared average pilot symbol energy, and
• dividing said sum of said average squared pilot symbol energy and said squared average pilot symbol energy by said average squared pilot symbol energy, and
• wherein said step of calculating said power control set point performs said calculation in accordance with said pilot variance.

In a wireless communications system, a method for power control independent of frame error rate, comprising:

• calculating a pilot channel bit error rate;
• calculating a normalized signal power variance, wherein the normalized signal power variance, (ρ), is calculated as:
• ρ = p ⁡ ( n ) 2 _ - p ⁡ ( n ) _ 2 p ⁡ ( n ) _ 2 = p ⁡ ( n ) 2 _ p ⁡ ( n ) _ 2 - 1
• where p(n) is the measured power of the nth frame, {overscore (p(n)2)} is the average of the squared energy of demodulated pilot symbols for a current frame, and {overscore (p(n))}2 is an average energy of the demodulated pilot symbols squared for the current frame;
• and
• determining a power control set point from the pilot channel bit error rate and the normalized signal variance.

In a wireless communications system, an apparatus for power control independent of frame error rate, comprising:

• means for calculating a pilot channel bit error rate;
• means for calculating a normalized signal power variance, wherein the normalized signal power variance, (ρ), is calculated as:
• ρ = p ⁡ ( n ) 2 _ - p ⁡ ( n ) _ 2 p ⁡ ( n ) _ 2 = p ⁡ ( n ) 2 _ p ⁡ ( n ) _ 2 - 1
• where p(n) is the measured power of the nth frame, {overscore (p(n)2)} is the average of the squared energy of demodulated pilot symbols for a current frame, and {overscore (p(n))}2 is an average energy of the demodulated pilot symbols squared for the current frame;
• and
• means for determining a power control set point from the pilot channel bit error rate and the normalized signal variance.

In a wireless communications system, an mobile station, comprising:

• a pilot energy calculator for calculating a pilot channel bit error rate;
• a pilot variance calculator for calculating a normalized signal power variance, wherein the normalized signal power variance, (ρ), is calculated as:
• ρ = p ⁡ ( n ) 2 _ - p ⁡ ( n ) _ 2 p ⁡ ( n ) _ 2 = p ⁡ ( n ) 2 _ p ⁡ ( n ) _ 2 - 1
• where p(n) is the measured power of the nth frame, {overscore (p(n)2)} is the average of the squared energy of demodulated pilot symbols for a current frame, and {overscore (p(n))}2 is an average energy of the demodulated pilot symbols squared for the current frame;
• and
• a set point calculator for determining a power control set point from the pilot channel bit error rate and the normalized signal variance.